chrono.cc build failure in maintainer-mode

[Paolo Carlini]

Ralf Wildenhues wrote:
> Aside, it seems weird that the compiler refers to && and || which do not
> occur in chrono.cc.  Wrong error location?
>
> Should I open a PR?
>   
I think you should, but the warning is doubly bogus, first because the
location is totally wrong, second because it's actually triggered by
this conditional inside an enable_if, which is fine and cannot be
"fixed" in any way:

           enable_if<treat_as_floating_point<rep>::value
             || (ratio_divide<_Period2, period>::type::den == 1
                 && !treat_as_floating_point<_Rep2>::value)>::type>
 
You can also guess it's bogus because it happens only for -fpic.

Thus, I say, please file a PR but a diagnostic one, **not** a library one.

Paolo.